Chovu malých jihoamerických cichlid rodů Laetacara a Nannacara se mohou věnovat i akvaristé, kteří své zálibě nemohou vyčlenit ve svém domově příliš velký prostor. Velkoryse pojaté akvaristické zázemí není v tomto případu nezbytné. Tyto rybky se starají o své potomstvo velmi starostlivě, takže lze při rozmnožování pozorovat různé projevy rodičovské péče., South American cichlids of the genera Laetacara and Nannacara can be bred also by aquarists without an elaborate aquarium equipment. These little fish look after their offspring very carefully, so various displays of parent care can be observed., and Jaroslav Eliáš.
Males in many beetles show horn or mandible dimorphism. The stag beetle Dorcus rectus was assumed to have dimorphic males, but in this species there are not two but three visually distinct mandibular phenotypes. The aim of this study is to determine if the three phenotypes represent an allometric trimorphism in this species by studying the scaling relationship between body length and mandible length in 148 adult males and 31 adult females. The relationship was fitted using the following four statistical models; a simple line, a logistic curve, a continuous segmented line and a discontinuous line. The best-fitting model for the males was a discontinuous line with two break points and that for the females a simple line. The male data was also well fitted by a logistic curve. The discontinuous linear model divided the males into three groups that were in good agreement with the three phenotypes. These results suggest that a subtle allometric trimorphism possibly exists in males of this species. Small males of this species have no distinct teeth on their mandibles, whereas small males of D. striatipennis and D. curvidens, which are closely related to D. rectus, have a pair of distinct teeth on their mandibles. The phylogenetic relationship of these Dorcus species suggests that the trimorphism in D. rectus may have arisen through the loss of teeth in small males., Yutaka Iguchi., and Obsahuje seznam literatury
Vodní toky v ČR jsou v posledních sto letech vystaveny intenzivnímu antropogennímu tlaku. Tyto činnosti se projevují také na populaci druhu marše pobřežní (Tetrix tuerki), který se vyskytuje se pouze na štěrkových lavicích podhorských potoků a řek. Národní přírodní památka Skalická Morávka je ideálním místem pro tento druh. Dynamika štěrkových lavic je velmi důležitá pro existenci tohoto druhu., Water flows have been under intensive anthropogenic pressure over the last 100 years. These activities also influenced populations of Tetrix tuerki, which only occurs on gravel benches of streams and rivers (dynamics of the benches are crucial for its existence). The National Natural Monument Skalická Morávka provides an ideal habitat., and Kateřina Kuřavová.
Keňská národní rezervace Masai Mara (též Maasai Mara) o rozloze 1 510 km2 se nachází ve Velké příkopové propadlině a přímo navazuje na národní park Serengeti v severní Tanzanii. Většinu jejího území pokrývají mírně zvlněné travnaté savany živené četnými srážkami v několika obdobích dešťů od listopadu do dubna. Pouze území v blízkém okolí řeky Mary a jejích přítoků jsou zalesněná. Rezervace je celosvětově proslulá mimořádně početnými migrujícími stády velkých kopytníků a jejich predátorů. V posledních desetiletích však populace některých druhů výrazně ubývají, za hlavní rizikové faktory se považuje rozšiřující se pastva skotu a nekontrolovaný rozvoj cestovního ruchu., Kenya’s Masai Mara National Reserve, covering an area of 1,510 km2, is situated in the Rift Valley with Tanzania’s Serengeti Plains running along its southern end. Most of the reserve is made up of hilly grassland, fed by plentiful rain, especially during the wet months between November and April. Only the areas near the Mara river and its tributaries are forested. The reserve is famous for its exceptional migrating populations of larger ungulates and its predators. However, the last decades have seen a considerable decrease in abundance of some species - the main causes are expanding livestock grazing and uncontrolled development of tourism., and Miloš Anděra.
Rezervaci Masai Mara proslavila především každoroční masová migrace pakoňů žíhaných (Connochaetes taurinus) a dalších kopytníků ze Serengeti (Tanzanie). Primární příčinou stěhování je střídání srážkového cyklu v rovníkové východní Africe a s tím související nabídka zelené potravy. Je ovšem obtížné určit přesný začátek či konec velkého stěhování – jde o neustále běžící cyklus, jehož jednotlivé fáze přecházejí plynule jedna v druhou. Navíc načasování migrací se rok od roku liší podle počasí i v řádu měsíců. Celá migrační trasa o délce zhruba 800 km má podobu nepravidelného oválu. Pohyb mnohatisícových až milionových stád přitahuje množství turistů z celého světa (druhé stěhování)., The Masai Mara reservation is famous for its annual mass migration of the Wildebeest (Connochaetes taurinus) and other hoofed animals from the Serengeti (Tanzania). Its primary cause is the changing precipitation cycle in equatorial east Africa, and the related supply of green food. It is difficult to determine exactly the beginning and the end of the Great Migration – it is a constantly running cycle, and its timing varies from year to year depending on weather conditions over a span of months. The entire route has a length of about 800 km. The movement of herds with hundreds of thousands to millions of animals attracts an ever-increasing number of tourists from around the world annually (the second migration)., and Miloš Anděra.
The trade-off between flight capability and reproduction is well known in adult males of insects with wing dimorphism but the reproductive advantage of short-winged (SW) males over long-winged (LW) males appears to vary across insect taxa. In the present study, we determined the difference in the mating ability of SW and LW males of Velarifictorus ornatus (Orthoptera: Gryllidae) in order to evaluate whether the SW male morph has a reproductive advantage. We found that the choice of a mate depended on the female. Compared with LW males, SW males had an obvious mating advantage when both SW and LW males courted females simultaneously, and that dealation significantly enhanced the mating ability of LW males. Losing the ability to produce songs reduced the mating advantage of SW males, thereby indicating that the greater mating advantage of SW males was related to the attractiveness of the song. In addition, the difference in the mating ability of LW and SW males was not related to body size or age. These results indicate that SW males of V. ornatus have a mating advantage over their LW counterparts because their underdeveloped flight muscles allow them to devote more resources to reproduction., Lv-Quan Zhao, Huai-Lin Chai, Hong-Jun Wu, Dao-Hong ZhuU., and Obsahuje bibliografii
The influence of female mating status on ovarian development of the ladybird, Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae), was investigated under laboratory conditions. We assessed the extent to which ovariole development was affected by mating and for that we initially created a base line by observing age specific ovariole development. Results show that the number of follicles in each ovariole increased with the age of both virgin and mated females up to the age of 3 days, thereafter, no increase in number of follicles was recorded. Ovariole width also increased with age in both virgin and mated females up to 4 days, thereafter, no increase in ovariole width was recorded. The ovariole width of mated females was significantly greater than that of virgin females. Egg maturation and the egg load started to increase at the age of 8 days in virgin females. Thereafter, it increased with increase in female age. While in mated females, immature eggs were recorded in their ovarioles from the age of 1 to 2 days. In mated females, however, the increase in the number of mature eggs per ovariole and egg load started when they were 3 days old. Egg load continuously increased with increasing female age., Mhd Shahid, Arshi Siddiqui, Omkar, Geetanjali Mishra., and Obsahuje bibliografii
Detailed knowledge of the circumstances behind the extermination of particular animal species is a key premise for their eventual return, reintroduction and ongoing preservation. Data on the presence of the Brown Bear (Ursus arctos) in the Czech landscape are usually limited to simple entries about the day and place where the last specimens in particular (usually mountainous) regions were slain. Demand for more precise data, especially regarding the last documented presence of bear cubs, has emerged in respect of the recently discovered ability of bears to migrate over long distances. The newly collected data allowed the author to present amuch more complete historical view of the process of extermination of the Brown Bear in the Czech territory. and Jan Andreska.